[libc++] Simplify __config a bit more and add underscores to attributes

[ldionne]

Typo in commit message. Also, you might want to say "add underscores to attribute names" just to clarify.

libcxx/include/__config

712

I would like to keep the definition of _LIBCPP_DECLARE_STRONG_ENUM[_EPILOG] the way it was. I think it makes sense for simple things like decltype and static_assert to be bulk-declared like you do above (in the new patch), but for more complicated things like this, it just obscures things out.

[philnik]

• Address comments

[philnik]

Rebased

libcxx/include/__config

 #  ifndef _LIBCPP_CXX03_LANG
 
 #    define _LIBCPP_ALIGNOF(_Tp) alignof(_Tp)
 #    define _ALIGNAS_TYPE(x) alignas(x)
 #    define _ALIGNAS(x) alignas(x)
 #    define _LIBCPP_NORETURN [[noreturn]]
 #    define _NOEXCEPT noexcept
 #    define _NOEXCEPT_(x) noexcept(x)
+#    define _LIBCPP_CONSTEXPR constexpr
 
 #  else
 
 #    define _LIBCPP_ALIGNOF(_Tp) _Alignof(_Tp)
 #    define _ALIGNAS_TYPE(x) __attribute__((__aligned__(_LIBCPP_ALIGNOF(x))))
 #    define _ALIGNAS(x) __attribute__((__aligned__(x)))
-#    define _LIBCPP_NORETURN __attribute__((noreturn))
+#    define _LIBCPP_NORETURN __attribute__((__noreturn__))
 #    define _LIBCPP_HAS_NO_NOEXCEPT
 #    define nullptr __nullptr
 #    define _NOEXCEPT throw()
 #    define _NOEXCEPT_(x)
+#    define static_assert(...) _Static_assert(__VA_ARGS__)
+#    define decltype(...) __decltype(__VA_ARGS__)
+#    define _LIBCPP_CONSTEXPR
 
 typedef __char16_t char16_t;
 typedef __char32_t char32_t;
 
 #  endif
 
 #  if !defined(__cpp_exceptions) || __cpp_exceptions < 199711L
 #    define _LIBCPP_NO_EXCEPTIONS

 #  if __has_attribute(__enable_if__)
 #    define _LIBCPP_PREFERRED_OVERLOAD __attribute__((__enable_if__(true, "")))
 #  endif
 
 #  ifndef __SIZEOF_INT128__
 #    define _LIBCPP_HAS_NO_INT128
 #  endif
 
-#  ifdef _LIBCPP_CXX03_LANG
-#    define static_assert(...) _Static_assert(__VA_ARGS__)
-#    define decltype(...) __decltype(__VA_ARGS__)
-#  endif // _LIBCPP_CXX03_LANG
-
-#  ifdef _LIBCPP_CXX03_LANG
-#    define _LIBCPP_CONSTEXPR
-#  else
-#    define _LIBCPP_CONSTEXPR constexpr
-#  endif
-
 #  ifndef __cpp_consteval
 #    define _LIBCPP_CONSTEVAL _LIBCPP_CONSTEXPR
 #  else
 #    define _LIBCPP_CONSTEVAL consteval
 #  endif
 
-#  ifdef __GNUC__
+#  if __has_attribute(__malloc__)
 #    define _LIBCPP_NOALIAS __attribute__((__malloc__))
 #  else
 #    define _LIBCPP_NOALIAS
 #  endif
 
-#  if __has_attribute(using_if_exists)
-#    define _LIBCPP_USING_IF_EXISTS __attribute__((using_if_exists))
+#  if __has_attribute(__using_if_exists__)
+#    define _LIBCPP_USING_IF_EXISTS __attribute__((__using_if_exists__))
 #  else
 #    define _LIBCPP_USING_IF_EXISTS
 #  endif
 
 #  ifdef _LIBCPP_CXX03_LANG
 #    define _LIBCPP_DECLARE_STRONG_ENUM(x)                                                                             \
       struct _LIBCPP_TYPE_VIS x {                                                                                      \
         enum __lx
 // clang-format off
 #    define _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(x)                                                                      \
       __lx __v_;                                                                                                       \
       _LIBCPP_INLINE_VISIBILITY x(__lx __v) : __v_(__v) {}                                                             \
       _LIBCPP_INLINE_VISIBILITY explicit x(int __v) : __v_(static_cast<__lx>(__v)) {}                                  \

 #  endif
 
 #  if _LIBCPP_STD_VER > 17
 #    define _LIBCPP_CONSTEXPR_AFTER_CXX17 constexpr
 #  else
 #    define _LIBCPP_CONSTEXPR_AFTER_CXX17
 #  endif
 
-#  if __has_cpp_attribute(nodiscard) || defined(_LIBCPP_COMPILER_MSVC)
+#  if __has_cpp_attribute(nodiscard)
 #    define _LIBCPP_NODISCARD [[nodiscard]]
-#  elif defined(_LIBCPP_COMPILER_CLANG_BASED) && !defined(_LIBCPP_CXX03_LANG)
-#    define _LIBCPP_NODISCARD [[clang::warn_unused_result]]
 #  else
 // We can't use GCC's [[gnu::warn_unused_result]] and
 // __attribute__((warn_unused_result)), because GCC does not silence them via
 // (void) cast.
 #    define _LIBCPP_NODISCARD
 #  endif
 
 // _LIBCPP_NODISCARD_EXT may be used to apply [[nodiscard]] to entities not
 // specified as such as an extension.
 #  if defined(_LIBCPP_ENABLE_NODISCARD) && !defined(_LIBCPP_DISABLE_NODISCARD_EXT)
 #    define _LIBCPP_NODISCARD_EXT _LIBCPP_NODISCARD
 #  else
 #    define _LIBCPP_NODISCARD_EXT
 #  endif
 
 #  if !defined(_LIBCPP_DISABLE_NODISCARD_AFTER_CXX17) && (_LIBCPP_STD_VER > 17 || defined(_LIBCPP_ENABLE_NODISCARD))
 #    define _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_NODISCARD
 #  else
 #    define _LIBCPP_NODISCARD_AFTER_CXX17
 #  endif
 
-#  if __has_attribute(no_destroy)
+#  if __has_attribute(__no_destroy__)
 #    define _LIBCPP_NO_DESTROY __attribute__((__no_destroy__))
 #  else
 #    define _LIBCPP_NO_DESTROY
 #  endif
 
 #  ifndef _LIBCPP_HAS_NO_ASAN
     extern "C" _LIBCPP_FUNC_VIS void
     __sanitizer_annotate_contiguous_container(const void*, const void*, const void*, const void*);

 #  ifdef _LIBCPP_HAS_THREAD_SAFETY_ANNOTATIONS
 #    define _LIBCPP_THREAD_SAFETY_ANNOTATION(x) __attribute__((x))
 #  else
 #    define _LIBCPP_THREAD_SAFETY_ANNOTATION(x)
 #  endif
 
 #  if _LIBCPP_STD_VER > 17
 #    define _LIBCPP_CONSTINIT constinit
-#  elif __has_attribute(require_constant_initialization)
+#  elif __has_attribute(__require_constant_initialization__)
 #    define _LIBCPP_CONSTINIT __attribute__((__require_constant_initialization__))
 #  else
 #    define _LIBCPP_CONSTINIT
 #  endif
 
-#  if __has_attribute(diagnose_if) && !defined(_LIBCPP_DISABLE_ADDITIONAL_DIAGNOSTICS)
-#    define _LIBCPP_DIAGNOSE_WARNING(...) __attribute__((diagnose_if(__VA_ARGS__, "warning")))
-#    define _LIBCPP_DIAGNOSE_ERROR(...) __attribute__((diagnose_if(__VA_ARGS__, "error")))
+#  if __has_attribute(__diagnose_if__) && !defined(_LIBCPP_DISABLE_ADDITIONAL_DIAGNOSTICS)
+#    define _LIBCPP_DIAGNOSE_WARNING(...) __attribute__((__diagnose_if__(__VA_ARGS__, "warning")))
 #  else
 #    define _LIBCPP_DIAGNOSE_WARNING(...)
-#    define _LIBCPP_DIAGNOSE_ERROR(...)
 #  endif
 
 // Use a function like macro to imply that it must be followed by a semicolon
 #  if __has_cpp_attribute(fallthrough)
 #    define _LIBCPP_FALLTHROUGH() [[fallthrough]]
 #  elif __has_attribute(__fallthrough__)
 #    define _LIBCPP_FALLTHROUGH() __attribute__((__fallthrough__))
 #  else

 
 // Support for _FILE_OFFSET_BITS=64 landed gradually in Android, so the full set
 // of functions used in cstdio may not be available for low API levels when
 // using 64-bit file offsets on LP32.
 #  if defined(__BIONIC__) && defined(__USE_FILE_OFFSET64) && __ANDROID_API__ < 24
 #    define _LIBCPP_HAS_NO_FGETPOS_FSETPOS
 #  endif
 
-#  if __has_attribute(init_priority)
-// TODO: Remove this once we drop support for building libc++ with old Clangs
-#    if (defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1200) ||                                                    \
-        (defined(__apple_build_version__) && __apple_build_version__ < 13000000)
-#      define _LIBCPP_INIT_PRIORITY_MAX __attribute__((init_priority(101)))
-#    else
-#      define _LIBCPP_INIT_PRIORITY_MAX __attribute__((init_priority(100)))
-#    endif
+#  if __has_attribute(__init_priority__)
+#    define _LIBCPP_INIT_PRIORITY_MAX __attribute__((__init_priority__(100)))
 #  else
 #    define _LIBCPP_INIT_PRIORITY_MAX
 #  endif
 
-#  if defined(__GNUC__) || defined(__clang__)
+#  if __has_attribute(__format__)
 // The attribute uses 1-based indices for ordinary and static member functions.
 // The attribute uses 2-based indices for non-static member functions.
 #    define _LIBCPP_ATTRIBUTE_FORMAT(archetype, format_string_index, first_format_arg_index)                           \
       __attribute__((__format__(archetype, format_string_index, first_format_arg_index)))
 #  else
 #    define _LIBCPP_ATTRIBUTE_FORMAT(archetype, format_string_index, first_format_arg_index) /* nothing */
 #  endif